Protection circuit board capable of easily checking welded state between electrode terminal and connection part thereof and secondary battery pack comprising the same

ABSTRACT

A protection circuit board includes a printed circuit board having a circuit is printed on a board formed from an electrically insulating material and two or more connection components disposed on at least one surface of the printed circuit board and are coupled to an electrode terminal of a secondary battery. Additionally, at least one inspection slot having a shape recessed within the connection component and extending to a portion that the electrode terminal of the secondary battery is coupled thereto and is defined in the connection component. Also, an inspection device and inspection method for inspecting a welded state between a protection circuit board and an electrode terminal among a pair of electrode terminals of a battery pack are provided.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Divisional of U.S. patent application Ser. No.15/799,375 filed on Oct. 31, 2017, which claims priority to KoreanPatent Application No. 10-2016-0143301 filed on Oct. 31, 2016, theentire contents of which are hereby expressly incorporated by referenceinto the present application.

BACKGROUND OF THE INVENTION Technical Field

The present disclosure relates to a protection circuit board and moreparticularly, a protection circuit board for more easily determining awelded state between an electrode terminal and a connection componentand a secondary battery including the same.

Background Art

Recently, demands of rechargeable secondary batteries have rapidlyincreased due to the increasing of technical development and demands ofmobile devices and the development of electric vehicles for replacinggasoline vehicles and diesel vehicles. Among the rechargeable secondarybatteries, lithium secondary batteries are widely used as energy sourcesfor various electronic products, electric vehicles and mobile devicesbecause the lithium secondary batteries have high energy density, highoperation voltage and improved battery life characteristics.

However, since the lithium secondary battery contains variouscombustibles, the lithium secondary battery has the possibility of riskthat includes overheating and explosion caused by overcharge,overcurrent, and external physical shock and thus, have a considerablesafety limitation. Accordingly, a protection circuit module (PCM) thateffectively controls an abnormal state such as overcharge is embedded inthe lithium secondary battery while being connected to the secondarybattery.

The PCM includes a field effect transistor (FET) that is a switchingelement that regulates a current and a passive element such as a voltagedetector, a resistor, and a condenser. The PCM may block the overcharge,overdischarge, overcurrent, short-circuit and inverse voltage of thesecondary battery to prevent the secondary battery from being exploded,overheated, or deteriorated in charge and discharge characteristics andsuppress degradation in electric performance and physical-chemicalabnormal behavior. Accordingly, the risk factor is reduced and thelifespan is extended. The PCM includes a protection circuit board (PCB)that the protection circuit is disposed on and a module case in whichthe PCB is accommodated. The battery pack is coupled to an exteriorsurface of a main body of the secondary battery when the PCB is coupledto the module case and is manufactured to be coupled to the secondarybattery.

Further, the PCB having a plate shape includes an electric conductiveconnection component disposed on one surface thereof to be electricallyconnected to the protection circuit and the main body of the battery andan external input-output terminal that is connected to an externaldevice such as a wireless terminal, a notebook and an electric vehicle.Accordingly, for electric connection between the PCB and the main bodyof the secondary battery electrode terminals of the secondary batteryare coupled to the connection components of the PCB through welding andsoldering.

In particular, although the connection component of the PCB is welded tothe electrode terminal, when the welding condition is insufficient, awelding coupling force therebetween may be minimal and be determined tobe a failure. As described above, when the inspection is performed onthe welded state of the secondary battery including the PCB,conventionally a welding quality is manually inspected for detachment ofthe electrode terminal using the inspection tip. Since forces applied tothe inspection tip vary during manual inspection and the electrodeterminal is deformed while being detached by the inspection tip, thewelding state inspection through the manual operation generates asecondary limitation.

FIG. 1 is exemplary photographs of the related art showing a weldedstructure between a PCB and an electrode terminal, depicting a manualinspection during a welded state using an inspection tip. As shown inFIG. 1, since an inspection is performed when the inspection tip isforcedly inserted between an electrode terminal and a connectioncomponent 20 of a PCB using an inspection method that manually detachesa welded portion using the inspection tip, the electrode terminal 10 isunavoidably damaged. Since the damaged electrode terminal 10 generatesincrease in resistance with a negative influence on a performance of thesecond battery, techniques for fundamentally solving a limitationgenerated in the above welded state process and a limitation on qualitydegradation in a process of manufacturing a battery are highly demanded.

The above information disclosed in this section is merely forenhancement of understanding of the background of the disclosure andtherefore it may contain information that does not form the prior artthat is already known in this country to a person of ordinary skill inthe art.

SUMMARY OF THE INVENTION

The present disclosure provides a protection circuit board for moreeasily determining a welded state between an electrode terminal and aconnection component and a secondary battery including the same. In anaspect of an exemplary embodiment of the present disclosure a protectioncircuit board may include a secondary battery having an electrodeterminal that is electrically and physically coupled to the protectioncircuit board to form a battery pack, a printed circuit board having acircuit printed on a board formed from an electrically insulatingmaterial and two or more connection components disposed on a surface ofthe printed circuit board and electrically and physically coupled to theelectrode terminal of a secondary battery. An inspection slot may have ashape recessed within the connection component and extending to aportion that the electrode terminal of the secondary battery is coupledto is defined in the connection component.

In some exemplary embodiments, the protection circuit board may includethe inspection slot having a cavity that an inspection tip passesthrough between the connection component and the electrode terminal tomonitor a coupling force therebetween when a connection component and anelectrode terminal of a secondary battery are coupled to each other. Inother exemplary embodiments, the protection circuit may include theconnection component having a conductive metal plate coupled to theelectrode terminal through welding when the connection component abutsthe electrode terminal of the secondary battery. In another exemplaryembodiment, the protection circuit board may include the connectioncomponent having a structure that includes at least two metal platesattached to the circuit board while being spaced a predetermineddistance from each other and an inspection slot may be formed by thecavity between the metal plates.

In other exemplary embodiments, the protection circuit board may includethe inspection slot having a depth that corresponds to a thickness ofthe metal plate with reference to the circuit board. In some exemplaryembodiments, the protection circuit board may include the connectioncomponent having a structure that includes four metal plates coupled tothe circuit board while being spaced a predetermined distance from eachother to form an inspection slot having a cross-shape on a plane.

In another exemplary embodiment, the protection circuit board mayinclude the connection component being a metal plate and the inspectionslot having a structure, in which the metal plate is recessed toward thecircuit board at a position that corresponds to a central portion of themetal plate. The protection circuit board may include the metal platehaving a recessed depth that is about 50% to about 90% of a thickness ofthe metal plate except for the inspection slot. The protection circuitboard may include the connection component having a portion of the metalplate except for the inspection slot coupled to the electrode terminalthrough resistance welding, ultrasonic welding, or laser welding.

The protection circuit board may include an end of the circuit boardhaving two or more recessed-type grooves and when the recessed-typegrooves are engaged with a projection disposed on a PCB accommodationcase or a pack housing of a battery pack, the circuit board may becoupled to the pack housing.

In another aspect of an exemplary embodiment, of the present disclosure,a battery pack may include a plate-type secondary battery having a pairof electrode terminals disposed in parallel to each other that protrudeoutward, a protection circuit board and a pack housing with theprotection circuit board and the secondary battery disposed therein.

In some exemplary embodiments, battery pack may include the battery packdisposed in a pack housing that includes at least two secondary batteryaccommodation components surrounding an outer circumferential surface ofthe secondary battery when a secondary battery array having electrodeterminals of a pair of secondary batteries are arrayed in a planararrangement to face each other has an opened top or bottom surface. Theprotection circuit board may be disposed in the pack housing when theconnection components of the protection circuit board are electricallyand physically coupled to the electrode terminal between the secondarybatteries facing each other. The battery pack may be disposed in thepack housing having at least one secondary battery accommodationcomponent surrounding an outer circumferential surface of the secondarybattery when at least one secondary battery has an opened top or bottomsurface and the protection circuit board may be coupled to the packhousing when the connection components of the circuit board areelectrically and physically coupled to the electrode terminals at anupper end portion of the pack housing.

In some exemplary embodiments, the battery pack may include a covermember coupled to the pack housing to cover the opened top or bottomsurface. The battery pack may include the pack housing having ananti-sliding projection configured to prevent displacement of thesecondary batteries at each position that corresponds to an end of thesecondary batteries where the electrode terminals are disposed and aprotrusion coupled to the recessed-type groove in the circuit board ofthe protection circuit board disposed on the anti-sliding projection.

In another exemplary embodiment, an inspection device for inspecting awelded state between the protection circuit board and the electrodeterminal of the battery pack may include at least two inspection tipsthat abut the electrode terminals when the inspection tips pass throughan inspection slot in the connection component and a jig having theinspection tips disposed thereon to position the inspection tips tocorrespond to the connection components and configured to apply apredetermined pressure to the inspection tips to push the electrodeterminals from the connection components by the inspection tips.

In another aspect an exemplary embodiment of the present disclosure amethod for inspecting a welded state between the electrode terminal andthe protection circuit board by using the inspection device may includeinserting at least two inspection tips into inspection slots ofconnection components different from each other and applying apredetermined pressure to the inspection tips to determine whether theelectrode terminal is separated from the connection component.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments may be understood in more detail from thefollowing description taken in conjunction with the accompanyingdrawings, in which:

FIG. 1 show exemplary photographs of a welded structure between anelectrode and a PCB, in which a welded state is inspected by a workerusing an inspection tip according to the related art;

FIG. 2 is an exemplary schematic view of a protection circuit board inaccordance with an exemplary embodiment of the present disclosure;

FIG. 3 is an exemplary schematic view of a connection component inaccordance with an exemplary embodiment of the present disclosure;

FIG. 4 is an exemplary schematic view of a connection component inaccordance with another exemplary embodiment of the present disclosure;

FIG. 5 is an exemplary schematic view of a connection component inaccordance with another exemplary embodiment of the present disclosure;

FIG. 6 is an exemplary schematic view of a battery pack in accordancewith an exemplary embodiment of the present disclosure;

FIGS. 7 and 8 are exemplary enlarged schematic views of a couplingstructure between a protection circuit board and a secondary batteryaccording to an exemplary embodiment of the present disclosure; and

FIG. 9 is an exemplary schematic view of a battery pack in accordancewith another exemplary embodiment of the present disclosure.

DETAILED DESCRIPTION

Hereinafter, specific embodiments will be described in detail withreference to the accompanying drawings. The present disclosure may,however, be embodied in different forms and should not be construed aslimited to the embodiments set forth herein.

Hereinafter, embodiments of the present disclosure will be describedwith reference to the accompanying drawings. However, the descriptionprovided herein is for better understanding of the present disclosure,and the scope of the present disclosure is not limited thereto. Indescribing the exemplary embodiments, thicknesses of lines and dimensionof components shown in the drawings may be expressed exaggeratedly forclarity and convenience of description. In addition, terms to bedescribed below are those defined in consideration of functions in thepresent disclosure, which may vary depending on intention or custom ofusers or operators. Therefore, definition of these terms should be madebased on the contents throughout this specification.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the disclosure.As used herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”and/or “comprising,” when used in this specification, specify thepresence of stated features, integers, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, integers, steps, operations, elements,components, and/or groups thereof. As used herein, the term “and/or”includes any and all combinations of one or more of the associatedlisted items. For example, in order to make the description of thepresent disclosure clear, unrelated parts are not shown and, thethicknesses of layers and regions are exaggerated for clarity. Further,when it is stated that a layer is “on” another layer or substrate, thelayer may be directly on another layer or substrate or a third layer maybe disposed therebetween.

It will be understood that, although the terms first, second, etc. maybe used herein to describe various elements, these elements should notbe limited by these terms. These terms are only used to distinguish oneelement from another. For example, a first element could be termed asecond element, and similarly, a second element could be termed a firstelement.

It will be further understood that the terms “comprises” and/or“comprising,” when used in this specification, specify the presence ofstated features, integers, steps, operations, elements, and/orcomponents, but do not preclude the presence or addition of one or moreother features, integers, steps, operations, elements, components,and/or groups thereof. As used herein, the term “and/or” includes anyand all combinations of one or more of the associated listed items.

Unless specifically stated or obvious from context, as used herein, theterm “about” is understood as within a range of normal tolerance in theart, for example within 2 standard deviations of the mean. “About” canbe understood as within 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, 0.5%,0.1%, 0.05%, or 0.01% of the stated value. Unless otherwise clear fromthe context, all numerical values provided herein are modified by theterm “about.”

The present disclosure is provided to solve a limitation of the relatedart and a technical subject requested from the past. In particular, thepresent disclosure provides a protection circuit board capable of moreeasily determining a welded state between an electrode terminal and aconnection component and preventing the terminal electrode and theconnection component from being damaged and a secondary batteryincluding the same.

In accordance with an exemplary embodiment, a protection circuit boardelectrically and physically coupled to an electrode terminal of asecondary battery to configure a battery pack may include a printedcircuit board having a circuit printed on a board formed from anelectrically insulating material and two or more connection componentsdisposed on a surface of the printed circuit board and electrically andphysically coupled to an electrode terminal of a secondary battery. Forexample, at least one inspection slot having a shape recessed within theconnection component and extending to a portion coupled to the electrodeterminal of the secondary battery is defined in the connectioncomponent.

In other words, since the inspection slot provides a cavity that aninspection tip to determine a coupling force therebetween passes betweenthe connection component and the electrode terminal when the connectioncomponent and the electrode terminal of the secondary battery arecoupled to each other, the protection circuit board in accordance withan exemplary embodiment may more easily determine a welded state betweenthe electrode terminal and the connection component and may prevent theelectrode terminal and the connection component from being damaged.

In an exemplary embodiment, the protection circuit board in accordancewith an exemplary embodiment may have a mechanical coupling structurefor more easily coupling the protection circuit board when a batterypack is formed. In particular, at least two recessed-type grooves may bedefined in an end of the circuit board, and as the recessed-type groovesare engaged with the protrusion provided on a PCB accommodation case ora pack housing of the battery pack, the circuit board may bemechanically coupled to the pack housing.

In an exemplary embodiment, the connection component formed from aconductive metal plate may be coupled to the electrode terminal throughwelding when the connection component abuts (e.g., is insurface-contact) with the electrode terminal of the secondary battery.In other words, the connection component may be a portion coupled to theelectrode terminal on the circuit board and as the metal plateconfiguring the connection component may be coupled to the electrodeterminal, the protection circuit board may be electrically coupled tothe secondary battery. Additionally, in the connection component, as atleast a portion of the metal plate except for the inspection slot may becoupled to the electrode terminal through resistance welding, ultrasonicwelding, or laser welding, the protection circuit board may bephysically coupled to the secondary battery.

In an exemplary embodiment, the connection component may have astructure with at least two metal plates coupled to the circuit boardwhile being spaced a predetermined distance from each other and aninspection slot may be a cavity between the metal plates. In theabove-described structure, the inspection slot may have a depth thatcorresponds to a thickness of the metal plate with reference to thecircuit board. The predetermined distance may represent a distance bywhich the inspection tip is coupled and a coupling surface area betweenthe electrode terminal and the connection component may be maximized. Inparticular, the predetermined distance may be about 5% to about 10% of alength of the electrode terminal disposed on the connection component.

The length of the electrode terminal disposed on the connectioncomponent may represent a longitudinal or transverse length of theelectrode terminal disposed on the connection component on a plane. Whenthe metal plates are spaced apart from each other in a direction thatcorresponds to a transverse of the electrode terminal, the predetermineddistance may be designed with reference to the width of the electrodeterminal. Additionally, when the metal plates are spaced apart from eachother in a direction that corresponds to the height of the electrodeterminal, the predetermined distance may be designed with reference tothe height of the electrode terminal. In some cases, the connectioncomponent may have a structure with four metal plates coupled to thecircuit board when being spaced a predetermined distance from each otherto form an inspection slot having a cross-shape on a plane.

In the above-described structure, when the inspection tip passes throughin each of the transverse and longitudinal directions, welded statesbetween the electrode terminal and the connection component in both thetransverse and longitudinal directions may be inspected. In an exemplaryembodiment, the connection component may be a metal plate. Theinspection slot having a structure with the metal plate recessed towardthe circuit board at a position that corresponds to a virtual linecrossing a central portion of the metal plate may be defined on themetal plate.

In the above-described structure, since, in the recessed structure ofthe metal plate, when the depth increases (e.g., is excessively deep)and the depth of the metal plate in the inspection slot is reduced,resistance at the inspection slot caused by carrying current mayincrease. On the contrary, when the thickness increases the metal platemay contact the electrode terminal and the inspection slot may bewelded. Accordingly, the inspection tip may not pass therethrough. Thus,in an exemplary embodiment, the metal plate may have a recessed depththat is about 50% to about 90% of a thickness of the metal plate exceptfor the inspection slot.

In accordance with another exemplary embodiment, a battery pack mayinclude at least one plate-type secondary battery having a pair ofelectrode terminals disposed in parallel to each other that protrudeoutward, a protection circuit board, and a pack housing with theprotection circuit board and the secondary battery disposed therein.

In an exemplary embodiment, the battery pack may be disposed in a packhousing that may include at least two secondary battery accommodationcomponents surrounding an outer circumferential surface of the secondarybattery when a secondary battery array having electrode terminals of apair of secondary batteries arrayed in a planar manner to face eachother has an opened top or bottom surface and the protection circuitboard may be disposed in the pack housing with the connection componentof the protection circuit board electrically and physically coupled toelectrode terminal between the secondary batteries facing each other.

In an exemplary embodiment, the battery pack may be disposed in the packhousing including at least one secondary battery accommodation componentsurrounding an outer circumferential surface of the secondary batterywhen at least one secondary battery has an opened top or bottom surfaceand the protection circuit board may be coupled to the pack housing whenconnection components of the circuit board are electrically andphysically coupled to the electrode terminals at an upper end portion ofthe pack housing. In an exemplary embodiment, the battery pack mayfurther include a cover member coupled to the pack housing to cover theopened top or bottom surface.

In an exemplary embodiment, the pack housing may have an anti-slidingprojection configured to prevent displacement of the secondary batteriesat each of the positions corresponding to ends of secondary batterieswhere the electrode terminals are disposed and a protrusion engaged withthe recessed-type groove defined in the circuit board of the protectioncircuit board may be disposed on the anti-sliding projection.Alternatively, the battery pack may have a structure with the electrodeterminal and the connection component of the protection circuit boardelectrically and physically coupled to each other and the pack housingmounted on an outer surface of the secondary battery when the protectioncircuit module having a structure with the protection circuit board isdisposed on the PCB accommodation case positioned on an upper end of thesecondary battery.

In accordance with another exemplary embodiment, an inspection devicefor inspecting a welded state between the protection circuit board andthe electrode terminal of the battery pack may include at least twoinspection tips that abut (e.g., closely contact) the electrodeterminals when the inspection tips pass through an inspection slotdefined in the connection component and a jig that the inspection tipsare disposed on at positions corresponding to the connection componentsand configured to apply a predetermined pressure to the inspection tipsto push the electrode terminals from the connection components by theinspection tips.

In accordance with still another exemplary embodiment, a method forinspecting a welded state between the electrode terminal and theprotection circuit board by using the inspection device may includeinserting at least two inspection tips into inspection slots ofconnection components different from each other and applying apredetermined pressure to the inspection tips to determine whether theelectrode terminal is separated from the connection component.

Although a type of the battery cell is not particularly limited, aspecific example of the batter cell may include a lithium secondarybattery such as a lithium ion battery and a lithium ion polymer batteryhaving high energy density, high discharge voltage, and outputstability. In general, the lithium secondary battery may include apositive electrode, a negative electrode, a separator, and a non-aqueouselectrolytic solution containing a lithium salt. The positive electrodemay be manufactured, e.g., by applying a mixture of a positive electrodeactive material, a conductive material, and a binder onto a positiveelectrode collector and/or an extended collecting component and thendrying, and when necessary, a filler may be further added to themixture.

In general, the positive current collector and/or the extended currentcollecting component may have a thickness of about 3 μm to about 500 μm.The positive current collector and the extended current collectingcomponent are not particularly limited as long as they have highelectrical conductivity without causing a chemical change in thecorresponding battery. For example, the positive electrode collector andthe extended current collecting component may be formed of stainlesssteel, aluminum, nickel, titanium, baking carbon or aluminum orstainless steel with a surface treated with carbon, nickel, titanium, orsilver. The collector may have an uneven surface to improve bondingstrength with an active material and be manufactured in various formssuch as a film, a sheet, foil, a net, a porous body, a foam body, or anon-woven fabric.

For example, electrode active material may be divided into a cathodeactive material and an anode active material. The cathode activematerial may include, for example, a layered compound such as lithiumcobalt oxide (LiCoO₂) and lithium nickel oxide (LiNiO₂) or a compoundsubstituted with one or more transition metals, a lithium manganeseoxide expressed as chemical formula Li1+yMn₂-yO₄ (where, y=0 to 0.33),LiMnO₃, LiMn₂O₃, and LiMnO₂; lithium copper oxide (Li₂CuO₂), vanadiumoxide such as LiV₃O₈, LiFe₃O₄, V₂O₅, Cu₂V₂O₇; a Ni site type lithiumnickel oxide expressed as chemical formula LiNi1-yMyO₂ (where, M=Co, Mn,Al, Cu, Fe, Mg, B or Ga and y=0.01 to 0.3), a lithium manganesecomposite oxide expressed as chemical formula LiMn₂-yMyO₂ (where, M=Co,Ni, Fe, Cr, Zn or Ta, and y=0.01 to 0.1) or Li₂Mn₃MO₈ (where, M=Fe, Co,Ni, Cu or Zn), LiMn₂O₄ in which a part of Li in the chemical formula issubstituted by alkali earth element ion; disulfide compound; andFe₂(MoO₄)₃, but it is not limited thereto.

The mixture including the positive electrode active material may includeabout 1% to about 50% by weight of the conductive material. Theconductive material is not particularly limited when it does not cause achemical change and has conductivity, which may include, for example,graphite such as natural graphite or artificial graphite; carbon blacksuch as carbon black, acetylene black, ketjen black, channel black,furnace black, lamp black, summer black; conductive fibers such ascarbon fibers and metallic fibers; metal powder such as carbon fluoride,aluminum, and nickel powder; conductive whiskers such as zinc oxide andpotassium titanate; conductive metal oxides such as titanium oxide; orconductive materials such as polyphenylene derivatives.

The binder may be an element to assist combining an active material withconductive material and combination of current collector, and typicallyadded by about 1 to about 30 weight % based on a total weight of amixture containing a cathode active material. For example, the bindermay include polyfluorovinylidene, polyvinyl alcohol, carboxymethylcellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose,polyvinyl pyrrolidone, tetrafluoroethylene, polyethylene, polypropylene,ethylene-propylene-diene-terpolymer (EPDM), sulfonated EPDM, stylenebutylene rubber, fluoro rubber or various copolymers.

A filler may be any material for suppressing swelling of the positiveelectrode, provided that the filler does not cause a chemical change inthe battery and has a fibrous structure. For example, the filler mayinclude an olefin-based copolymer such as polyethylene andpolypropylene; or a fibrous material such as glass fiber and carbonfiber. The negative electrode may be formed by applying a negativeelectrode material on the negative electrode collector and drying it andmay include the above-described components.

In general, the positive current collector and/or the extended currentcollecting component may have a thickness of about 3 μm to about 500 μm.The negative current collector and/or the extended current collectingcomponent are not particularly limited as long as they have electricalconductivity without causing a chemical change in the correspondingbattery. For example, the negative current collector may include copper,stainless steel, aluminum, nickel, titanium, baking carbon, copper orstainless steel with a surface treated with carbon, nickel, titanium, orsilver, or an aluminum-cadmium alloy. Also, like the cathode collector,the anode collector may have an uneven surface to improve bondingstrength with an active material and be manufactured in various formssuch as a film, a sheet, foil, a net, a porous body, a foam body or anon-woven fabric.

The anode active material may include, carbon such as graphitizingcarbon and graphite-based carbon; a complex metal oxide such asLixFe₂O₃(0≤x≤1), LixWO2(0≤x≤1), and SnxMe1-xMe′yOz (Me: Mn, Fe, Pb, Ge;Me′: Al, B, P, Si, Group 1, Group 2, and Group 3 elements of thePeriodic Table, halogen; 0<x≤1; 1≤y≤3; 1≤z≤8); lithium metal; lithiumalloy; silicon-based alloy; tin-based alloy; metal oxide such as SnO,SnO₂, PbO, PbO₂, Pb₂O₃, Pb₃O₄, Sb₂O₃, Sb₂O₄, Sb₂O₅, GeO, GeO₂, Bi₂O₃,Bi₂O₄, and Bi₂O₅; conductive polymers such as polyacetylene and Li—Co—Nibased materials.

The separator may be interposed between the positive electrode and thenegative electrode and an insulating thin film having high ionpermeability and mechanical strength may be used as the separator. Theseparator may have a pore diameter of about 0.01 μm to about 10 μm and athickness of about 5 μm to about 300 μm. For example, the separator mayinclude an olefin-based polymer such as polypropylene that has chemicalresistance and hydrophobicity and a sheet or a non-woven fabric made ofa glass fiber and polyethylene. When a solid electrolyte such as apolymer is used as the electrolyte, the solid electrolyte may serve asthe separator.

The electrolytic solution may be the non-aqueous electrolytic solutioncontaining the lithium salt, which includes the non-aqueous electrolyticsolution and the lithium salt. The non-aqueous electrolytic solution mayinclude a non-aqueous organic solution, an organic solid electrolyte,and an inorganic solid electrolyte, but is not limited thereto. Forexample, the non-aqueous electrolyte may include an aprotic organicsolvent such as N-methyl-2-pyrrolidone, propylene carbonate, ethylenecarbonate, butylene carbonate, dimethyl carbonate, diethyle carbonate,gamma-butyrolacton, 1,2-dimethoxy ethane, tetrahydroxy franc, 2-methyltetrahydrofuran, dimethyl sulfoxide, 1,3-dioxolane, formamide, dimethylformamide, dioxolane, acetonitrile, nitromethane, methyl formate, methylacetate, phosphoric acid tri-ester, trimethoxy methane, dioxolanederivatives, sulfolan, methyl sulfolan, 1,3-dimethyl-2-imidazolidinone,a propylene carbonate derivative, a tetrahydrofuran derivative, ether,methyl propionate, and ethyl propionate.

For example, the organic solid electrolyte may include a copolymerincluding a polyethylene derivative, a polyethylene oxide derivative, apolypropylene oxide derivative, a phosphoric acid ester polymer, polyagitation lysine, polyester sulfide, polyvinyl alcohol, poly vinylidenefluoride, or an ionic disintegrator.

For example, the inorganic solid electrolyte may include an Li-basednitride such as Li₃N, LiI, Li₅NI₂, Li₃N—LiI—LiOH, LiSiO₄,LiSiO₄—LiI—LiOH, Li₂SiS₃, Li₄SiO₄, Li₄SiO₄—LiI—LiOH, andLi₃PO₄—Li₂S—SiS₂, a nitride, a halide, or a sulfate.

For example, the lithium salt may include a material easily dissolved inthe non-aqueous electrolyte, such as LiCl, LiBr, LiI, LiClO₄, LiBF₄,LiB₁₀Cl₁₀, LiPF₆, LiCF₃SO₃, LiCF₃CO₂, LiAsF₆, LiSbF₆, LiAlCl₄, CH₃SO₃Li,CF₃SO₃Li, (CF₃SO₂)₂NLi, lithium chloroborane, lithium lower aliphaticcarbonate, lithium 4-phenyl borate, imide and the like.

Further, the following compounds may be added to the non-aqueouselectrolyte in order to improve discharge and charge characteristics andflame retardancy. Examples include pyridine, triethyl phosphite,triethanolamine, cyclic ether, ethylenediamine, n-glyme, hexaphosphorictriamide, a nitrobenzene derivative, sulfur, a quinone-imine dye,N-substituted oxazolidinone, N,N-substituted imidazolidine, ethyleneglycol dialkyl ether, an ammonium salt, pyrrole, 2-methoxyethanol, andaluminum trichloride. In order to provide incombustibility to theelectrolyte, the electrolyte may further include a halogen-containingsolvent such as carbon tetrachloride and ethylene trifluoride. Further,in order to improve high-temperature storage characteristics, theelectrolyte may include carbon dioxide gas.

In an exemplary embodiment, the non-aqueous electrolyte containing thelithium salt may be prepared by adding the lithium salt such as, LiPF₆,LiClO₄, LiBF₄, LiN(SO₂CF₃)₂ into a high dielectric solution such as ECor a mixed solution in which cyclic carbonate of OC and chain carbonateof a low viscous solution such as DEC, DMC, or EMC are mixed.

Hereinafter, specific embodiments will be described in detail withreference to the accompanying drawings. The present disclosure may,however, be embodied in different forms and should not be construed aslimited to the embodiments set forth herein.

FIG. 2 is an exemplary schematic view of a protection circuit board 100in accordance with an exemplary embodiment. Referring to FIG. 2, theprotection circuit board 100 may include a circuit board 120 having acircuit printed on a board formed from an electric insulation materialand a plurality of connection components 110 disposed on one surface ofthe circuit board 120 and coupled to an electrode terminal of asecondary battery in an electrical and physical manner.

Additionally, the protection circuit board 100 may further include anexternal input-output (I/O) cable 104 disposed on one side end of thecircuit board 120 and connectable to an external device. A recessedgroove 122 may be disposed in other ends of the circuit board 120. Forexample, as illustrated in FIG. 6, the recessed groove 122 may engagewith a protrusion 324 disposed on a pack housing 320 of the battery pack300, to enable the circuit board 120 to be mechanically coupled to thepack housing 320. An inspection slot having a recessed inward theconnection component 110 and extending to a portion that the electrodeterminal of the secondary battery are coupled to may be defined in eachof the connection components 110. The connection components 110 and theinspection slot are illustrated in detail in FIGS. 3 to 5 as anexemplary embodiment.

Referring to FIG. 3, the connection component 110 a may include twometal plates 112 and 114. The metal plates 112 and 114 may be coupled tothe circuit board 120 while being spaced a predetermined distance fromeach other. For example, the inspection slot 116 may be a cavity betweenthe metal plates 112 and 114 and the inspection slot 116 may have adepth that corresponds to the thickness of each of the metal plates 112and 114 with reference to the circuit board 120. In other words, theconnection component 110 a may be a portion coupled to the electrodeterminal on the circuit board 120. When the metal plates 112 and 114configuring the connection component 110 are coupled to the electrodeterminal, the PCB and the secondary battery may be electricallyconnected to each other.

Conversely, when a structure of the connection component 110 b in FIG. 4is reviewed, the connection component 110 b may have the structure withfour metal plates 212, 214, 216, and 218 coupled to the circuit boardwhile being spaced a predetermined distance from each other to form theinspection slot 220 having a cross shape on a plane. Since theinspection slot 220 provides a passage in longitudinal and transversedirections through the above-described structure, a welded state betweenthe electrode terminal and the connection component 110 b in transverseand longitudinal directions may be inspected when the inspection tip isinserted into the passage.

Further, a connection component 110 c as shown in FIG. 5 may include onemetal plate 250. For example, an inspection slot 252 having a structurewith the metal plate 250 recessed toward the circuit board 120 may bedefined in the metal plate 250 at a position corresponding to a virtualline crossing a central portion of the metal plate 250.

FIG. 6 is an exemplary schematic view illustrating a structure of abattery pack 300 in accordance with an exemplary embodiment. FIGS. 7 and8 are exemplary schematic views illustrating a coupling structurebetween a protection circuit board 100 and a secondary battery.Referring to FIGS. 6 to 7 in conjunction with FIGS. 2 and 3, the batterypack 300 may include the secondary battery 310 coupled to the packhousing 320 including accommodation components that each accommodate onesecondary battery and surround an outer circumferential surface of thesecondary battery 310 when a top surface of the secondary battery 310 isopened. The protection circuit board 100 may be coupled to an upper endportion of the pack housing 320 when the connection component 110 of theprotection circuit board 100 is electrically and physically coupled tothe electrode terminals.

Although not separately shown in the drawings, the battery pack 300 mayfurther include a cover member (not shown) coupled to the top surface ofthe pack housing 320 to surround the opened top surface of the packhousing 320. Anti-sliding projection 322 for preventing the secondarybatteries from being slid may be disposed at positions that correspondto ends of the secondary batteries, at which the electrode terminals 312are disposed. Additionally, a protrusion 324 engaged with the recessedgroove 122 disposed on the circuit board 120 of the circuit protectionboard 100 is provided on the anti-sliding projection. When theprotrusion 324 is engaged with the recessed groove 122, the protectioncircuit board 100 may be coupled to the pack housing 320.

The connection component 110 of the protection circuit board 100 may becoupled to the electrode terminal 312 through a spot welding when themetal plates 112 and 114 thereof are in surface-contact with theelectrode terminal 312 of the secondary battery 310. For example, sincethe inspection slot 116 has a recessed structure, the inspection slot116 is not in surface-contact with the electrode terminal 312.Accordingly, the inspection slot 116 provides a space through which theinspection tip 15 passes between the connection component 110 and theelectrode terminal 312 to determine a coupling force therebetween whenthe connection component 110 and the electrode terminal 312 of thesecondary battery 310 are coupled to each other. Accordingly, thepresent disclosure provides a technique capable of more easilydetermining a welded state between the electrode terminal and theconnection component and preventing the electrode terminal and theconnection component from being damaged during an inspection process.

FIG. 9 is an exemplary schematic view of a battery pack 400 inaccordance with another exemplary embodiment. Referring to FIG. 9, thebattery pack 400 may be coupled to a housing 320 including two or morebattery cell accommodation components surrounding outer circumferentialsurface of the secondary batteries 410 a and 410 b when a top surface ofa battery cell array 410 having electrode terminals of the secondarybatteries 410 a and 410 b arranged in a planar manner to position theelectrode terminals to face each other. A protection circuit board 100may be coupled to a pack housing 320 when a connection terminal 110 ofthe protection circuit board 100 is electrically and physically coupledto electrode terminals between the secondary batteries 410 a and 410 bfacing each other. Although not separately shown in the drawings, thebattery pack 300 may further include a cover member coupled to a topsurface of the pack housing 320 to surround the opened top surface ofthe pack housing 320.

As described above, when the protection circuit board in accordance withthe exemplary embodiment include the inspection slot formed in astructure in which the inspection slot provides a cavity through whichthe inspection tip for determining the coupling force passes throughbetween the connection component and the electrode terminal when theconnection component and the electrode terminal of the secondary batteryare coupled to each other, the welded state between the electrode andthe connection component may be more easily determined and the electrodeterminal and the connection component may be prevented from beingdamaged during the inspection process.

Although the exemplary embodiments of the present disclosure have beendescribed, it is understood that the present disclosure should not belimited to these exemplary embodiments but various changes andmodifications can be made by one ordinary skilled in the art within thespirit and scope of the present disclosure as hereinafter claimed.

What is claimed is:
 1. An inspection device for inspecting a weldedstate between a protection circuit board and an electrode terminal amonga pair of electrode terminals of a battery pack, the inspection devicecomprising: at least two inspection tips that abut the pair of electrodeterminals when the at least two inspection tips pass through aninspection slot in a connection component among a plurality ofconnection components disposed on a surface of a printed circuit boardof the protection circuit board; and a jig having the at least twoinspection tips disposed thereon to position the at least two inspectiontips to correspond to the plurality of connection components andconfigured to apply a predetermined pressure to the at least twoinspection tips to push the pair of electrode terminals from theplurality of connection components by the at least two inspection tips.2. The inspection device of claim 1, wherein one of the at least twoinspection tips is configured to use a cavity of the inspection slot todetermine a coupling force between the connection component and theelectrode terminal when the connection component and the electrodeterminal of the battery pack are coupled to each other.
 3. Theinspection device of claim 2, wherein the inspection slot has a shaperecessed within the connection component of the plurality of connectioncomponents and extends to a portion of the connection component that iscoupled to the electrode terminal, wherein the electrode terminal andthe connection component of the plurality of connection components areface to face connected at connected faces thereof, and the inspectionslot is arranged between the connected faces, and wherein the one of theat least two inspection tip is inserted into the cavity to determine thecoupling force.
 4. The inspection device of claim 3, wherein theconnection component includes a conductive metal plate coupled to theelectrode terminal via welding when the connection component abuts theelectrode terminal.
 5. The inspection device of claim 4, wherein theconnection component has a structure that includes the conductive metalplate being a plurality of metal plates coupled to the printed circuitboard while being spaced at a predetermined distance from each other,and the inspection slot is formed by the cavity between the plurality ofmetal plates.
 6. The inspection device of claim 2, wherein theinspection slot is arranged to bisect the connection component, and theelectrode terminal is arranged to intersect the inspection slot.
 7. Amethod for inspecting a welded state between the protection circuitboard and the electrode terminal by using the inspection device of claim1, the method comprising: inserting the at least two inspection tipsinto the inspection slot in the connection component of the plurality ofconnection components different from each other; and applying apredetermined pressure to the at least two inspection tips to determinewhether the electrode terminal is separated from the connectioncomponent of the plurality of connection components.